Improved telegraphic cable



PATENT@ SEPT. 27, 1859;

jfs. DAvIsoN. TELEGRAPHIG CABLE.

UNITED STATES PATENT OFFICE.

J. s. DAvrsoN, or GEANEEREY, NEW JERSEY.

IMPROVED TELEGRAPHI'C CABLE.

Specication forming part of Letters Patent No. 25,562, dated September27, 1859.

To all whom it may concern:

Be it known that I, J S. DAWSON, of Cram' berry, in the county ofMiddlesex and State ot' New Jersey, have invented a new and 11np rovedTelegraph-Gable 5 and I do hereby declare thatthe following is a full,clear, and exact description of the same, reference beingV had to theaccompanying drawings, forming a part of this specification, in which-Figure 1 represents a sectional elevation ot" my invention. Fig. 2 is atransverse vertical section of same.

Similar letters of reference in both views indicate correspondingpart's.-

Telegraph-cables which, when they are submerged in deep water, aresubjected to a certain strain 'have to be so arranged that thevconductor is fully protected against all injurious influences et thisstrain. A straight wire stretched from end to end surrounded by a coiland bythe insulating substance will certainly break when the cable issubmerged, for a comparatively small strain will cause the coil tostretch, and the conducting-wire, together with the insulatingsubstance, has to support the whole weight of that portion oi' the cablewhich may be suspended between the surface and the bottom ofthe water.The conductor must either be protected in such a manner that saidprotection is able to withstand the strain without being stretched, or,if the protection stretches, the conductor must be so constructed thatit can stretch also without bein gV injured.

With my cable the conductor is protected by a coil, which, of course,will stretch it' it is subjected to a strain, and the conductor itselfconsists of a series of loose strips of copper wire that are'hooked onor otherwise united to the coil and which fill np the space in theinside of the coil, so that when the coil stretches each of said stripsassumes a longitudinal sliding motion, and as the c oil by beingstretched diminishes itsdiameter said strips are brought close togetherand the current passes through without interruption. l

To enable those skilled in the art to make and use my invention, I willproceed to describe it.

A represents a coil of copper wire or of any other suitable metal. Ironmay be used, it' desired, as the coil is not used as a conductor.

. This coil is, surrounded by an insulating-tube, B, and its interior isfilled up by a series ot'- loose strips of copper wire, a. Each striplmay be made of any desirable length, and each 0l" them is fastened tothe coil with one end by means of hooks b or in any other convenientmanner. assumes a longitudinal sliding motion, and as the diameter ofthe coil diminishes when the same is stretched the loosestrips arebrought closer. in contact, andl the current, passes throng-h without'interruption. These looseI strips ought to be made of copper wire orsilver wire, as it is desirable that the conductor v of the cable offersas .little resistance as pos- When the coil stretches each strip

